Evaluation of mediastinal lymph node metastasis in lung cancer: factors influencing the diagnostic accuracy of CT

The purpose of this paper is to evaluate factors influencing the CT assessment of mediastinal lymph node metastasis in patients with non-small cell lung cancer. CT scans of 198 patients who had undergone thoracotomy and mediastinal lymph node dissection for non-small cell lung cancer were retrospectively evaluated using a size criterion of ≥ 10mm in the short axis. To evaluate the accuracy of CT in diagnosing lymph node metastasis on a nodal station-by-station basis, CT and pathological results were correlated. Analysis included a comparison of the sensitivity and specificity of CT according to 1) cell type of tumor, squamous cell carcinoma versus adenocarcinoma (excluding bronchioloalveolar cell carcinoma); 2) histologic differentiation; 3) tumor size ; 4) central and peripheral location of the tumor; 5) the presence or absence of obstructive pneumonitis and /or atelectasis; 6) the presence or absence of prior granulomatous disease. In the CT assessment of mediastinal lymph node metastasis the cell type of adenocarcinoma adversely affected sensitivity, with a high frequency of normal-sized metastatic nodes. Obstructive pneumonitis caused by central tumor adversely affected specificity with the frequent occurrence of hyperplastic nodes. (author). 16 refs., 2 figs